iMac | 3.2 GHz Core i5 | 27 Inch | Late 2013 - Techable.com
New CPUs, faster Wi-Fi, same flaws: Apple's 2013 iMac reviewed | Ars Technica
OWC 16GB (2x8GB) ram Upgrade PC3-12800 DDR3L 1600MHz sodimm 204 Pin CL11 Memory Upgrade Kit Compatible with Late iMac, Mac Mini, and MacBook Pro Computer at Amazon.com
iMac | 2.7 GHz Intel i5 | 21.5 Inch | Late 2013 - Techable.com
Apple iMac (27-inch, September 2013) review: New processors and faster Wi-Fi for Apple's slim desktop - CNET
Install memory in an iMac - Apple Support
A-Tech 32GB Kit (4x8GB) RAM for Apple iMac (Late 2012, Late 2013, Late 2014, Mid 2015) | DDR3 1600MHz PC3-12800 SODIMM 204-Pin Memory Upgrade at Amazon.com
iMac | 3.1 GHz Intel i7 | 21.5 Inch | Late 2013 - Techable.com
Memory Upgrades for iMac 21.5-Inch 2012 - Late 2013
Apple Mac Pro review (2013) - The Verge
Late 2013 27-inch iMac: Unboxing and Specs (HD) - YouTube
Adamanta 16GB (2x8GB) Apple Memory Upgrade DDR3L 1600MHz SODIMM Compatible for iMac (Mid 2011, Late 2012, Early/Late 2013, Late 2014, Mid 2015), MacBook Pro (Early/Late 2011, Mid 2012), Mac Mini RAM at Amazon.com
iMac RAM upgrade: Here's an affordable way to improve multitasking - CNET
Apple iMac 21.5-inch and 27-inch (Late 2013) reviews | Macworld
iMac (27-inch, Late 2013) - Technical Specifications
Install memory in an iMac - Apple Support
iMac 21.5-inch Late 2013 – Full Tech Specs, Release Date, and Price
iMac (Retina 5K, 27-inch, Late 2014) - Technical Specifications